From: Paolo Abeni pabeni@redhat.com
commit 1249db44a102d9d3541ed7798d4b01ffdcf03524 upstream.
Currently the subflow error report callback unconditionally propagates the fallback subflow status to the owning msk.
If the msk is already orphaned, the above prevents the code from correctly tracking the msk moving to the TCP_CLOSE state and doing the appropriate cleanup.
All the above causes increasing memory usage over time and sporadic self-tests failures.
There is a great deal of infrastructure trying to propagate correctly the fallback subflow status to the owning mptcp socket, e.g. via mptcp_subflow_eof() and subflow_sched_work_if_closed(): in the error propagation path we need only to cope with unorphaned sockets.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/339 Fixes: 15cc10453398 ("mptcp: deliver ssk errors to msk") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/subflow.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1344,6 +1344,7 @@ void __mptcp_error_report(struct sock *s mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); int err = sock_error(ssk); + int ssk_state;
if (!err) continue; @@ -1354,7 +1355,14 @@ void __mptcp_error_report(struct sock *s if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk)) continue;
- inet_sk_state_store(sk, inet_sk_state_load(ssk)); + /* We need to propagate only transition to CLOSE state. + * Orphaned socket will see such state change via + * subflow_sched_work_if_closed() and that path will properly + * destroy the msk as needed. + */ + ssk_state = inet_sk_state_load(ssk); + if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD)) + inet_sk_state_store(sk, ssk_state); sk->sk_err = -err;
/* This barrier is coupled with smp_rmb() in mptcp_poll() */